230 Messrs. J. A. Gardner and P. E. Lander. Origin and 



cholesterol ester content of day-old chicks, and chicks at various stages of 

 growth. 



Method of Estimation of the Cholesterol. 



The weighed chickens were minced in a mincing machine and the minced 

 mass was pounded up in a mortar with sand and sufficient plaster of Paris 

 to cause the whole to set after a time to a dry mass, which was powdered 

 and then extracted with ether in a Soxhlet's apparatus for about a fortnight. 

 The ethereal solution of the extract was made up to a known volume and 

 suitable aliquot proportions taken for analysis. The analyses were made 

 by a modification of Windaus' digitonin method devised by Fraser and 

 Gardner.* 



General Plan of Experiments. 



Fifty-four white Wyandotte day-old chicks of the same strain were 

 obtained from a dealer and six of these were killed straight away and analysed 

 with the following result. 



The weight of the six chickens was 212 grin., and the extract was made up 

 to 1 litre ; 100 c.c. of this extract were then taken, and by direct precipitation 

 gave 0-3407 grm. of the compound, corresponding to 0'0828 grm. of 

 cholesterol, whilst 100 c.c. after saponification gave 0'49 grm. of the compound 

 corresponding to - 1189 grm. of cholesterol. 



The remaining chickens were placed in four pens A, B, C, and D, as 

 nearly as possible under the same conditions, 10 in A, 10 in B, 14 in C, and 

 14 in D. Each pen consisted of a foster mother, kept at a suitable uniform 

 temperature by electric means, and was provided with a run with a sandy 

 floor in which was placed a trough of water, and in which the animals were 

 fed. Three diets were made use of. 



(1) An ordinary commercial chicken food, of approximately the following 

 composition : — 



Per cent. Per cent. 



Water 9-65 Fats 2-25 



Proteins 22'50 Ash T20 



Carbohydrates 64 - 40 



(2) The same chicken food as the above, which had previously been freed 

 as far as possible from fats, cholesterol and phytosterol. In this food the 

 percentage of protein was found to be about 19 - 9 per cent. 



(3) The same diet as in (2), but with the addition of about 2 per cent, of 

 cholesterol. 



In the case of the first two meals given to the chickens, the diet (1) was 

 * Fraser and Gardner, 'Koy. Soc. Proc.,' 1910, B, vol. 82, p. 560. 



